981 research outputs found

    Deep Space Network information system architecture study

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    The purpose of this article is to describe an architecture for the Deep Space Network (DSN) information system in the years 2000-2010 and to provide guidelines for its evolution during the 1990s. The study scope is defined to be from the front-end areas at the antennas to the end users (spacecraft teams, principal investigators, archival storage systems, and non-NASA partners). The architectural vision provides guidance for major DSN implementation efforts during the next decade. A strong motivation for the study is an expected dramatic improvement in information-systems technologies, such as the following: computer processing, automation technology (including knowledge-based systems), networking and data transport, software and hardware engineering, and human-interface technology. The proposed Ground Information System has the following major features: unified architecture from the front-end area to the end user; open-systems standards to achieve interoperability; DSN production of level 0 data; delivery of level 0 data from the Deep Space Communications Complex, if desired; dedicated telemetry processors for each receiver; security against unauthorized access and errors; and highly automated monitor and control

    On Recommendation of Learning Objects using Felder-Silverman Learning Style Model

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    The file attached to this record is the author's final peer reviewed version. The Publisher's final version can be found by following the DOI link.The e-learning recommender system in learning institutions is increasingly becoming the preferred mode of delivery, as it enables learning anytime, anywhere. However, delivering personalised course learning objects based on learner preferences is still a challenge. Current mainstream recommendation algorithms, such as the Collaborative Filtering (CF) and Content-Based Filtering (CBF), deal with only two types of entities, namely users and items with their ratings. However, these methods do not pay attention to student preferences, such as learning styles, which are especially important for the accuracy of course learning objects prediction or recommendation. Moreover, several recommendation techniques experience cold-start and rating sparsity problems. To address the challenge of improving the quality of recommender systems, in this paper a novel recommender algorithm for machine learning is proposed, which combines students actual rating with their learning styles to recommend Top-N course learning objects (LOs). Various recommendation techniques are considered in an experimental study investigating the best technique to use in predicting student ratings for e-learning recommender systems. We use the Felder-Silverman Learning Styles Model (FSLSM) to represent both the student learning styles and the learning object profiles. The predicted rating has been compared with the actual student rating. This approach has been experimented on 80 students for an online course created in the MOODLE Learning Management System, while the evaluation of the experiments has been performed with the Mean Absolute Error (MAE) and Root Mean Square Error (RMSE). The results of the experiment verify that the proposed approach provides a higher prediction rating and significantly increases the accuracy of the recommendation

    A Multimedia Interactive Environment Using Program Archetypes: Divide-and-Conquer

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    As networks and distributed systems that can exploit parallel computing become more widespread, the need for ways to teach parallel programming effectively grows as well. Even though many colleges and universities provide courses on parallel programming [1], most of those courses are reserved for graduate students and advanced undergraduates. There is a demand for ways to teach fundamental parallel programming concepts to people with just a working knowledge of programming. By using the idea of a software archetype, and providing a learning environment that teaches both concept and coding, we hope to satisfy this need. This paper presents an overview of the multimedia approach we took in teaching parallel programming and offers Divide-and-Conquer as an example of its use

    A state of art survey on zz-structures

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    Zz-structures are particular data structures capable of representing both hypertextual information and contextual interconnections among different information. The focus of this paper is to stimulate new research on this topic, by providing, in a state of the art survey, a short description and comparison of all the material that, to the best of our knowledge, is related to zz-structures: informal and formal descriptions, implementations, languages, demonstrations, projects and applitudes of zz-structures; in fact, despite their large use in different fields, the literature lacks of an exhaustive and up-to-date description of them

    Teaching Archetypal Design with an Electronic Textbook

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    How can parallel programming be made tractable for students in high schools and community colleges, to programmers in four-year colleges, to commercial and government employees, to interested independent users learning on their own, and as CASE tools for professional software designers? The computer science community must address this question if the ability of programmers to harness the power of parallel systems is to maintain pace with technology advances forthcoming in parallel systems. This paper addresses some of the issues of bringing parallel programming to the people, ranging from newly developing programmers with little experience on any computer to seasoned programmers of single-processor machines. We aim not only to enable people to use more powerful computers, but also to enable people to use computers more powerfully, by nurturing the techniques that enable them to develop efficient, correct code with relative ease. This paper briefly presents the concept of an Archetype, a software engineering methodology developed at the Caltech for patterns of problem solving, and for providing media for quick reference and natural software reuse. We then describe eText, an interactive multimedia electronic textbook that facilitates the teaching of, navigating through, and referring to Archetypes. Initial experience with Archetypes and the electronic textbook suggests that this approach to teaching parallel programming can aid computer users in the immediate future

    Synthetic movies

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    Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Architecture, 1989.Includes bibliographical references (leaves 67-70).by John A. Watlington.M.S

    Analyzing web server performance under dynamic user workloads

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    The increasing popularity of web applications has introduced a new paradigm where users are no longer passive web consumers but they become active contributors to the web, specially in the contexts of social networking, blogs, wikis or e-commerce. In this new paradigm, contents and services are even more dynamic, which consequently increases the level of dynamism in user's behavior. Moreover, this trend is expected to rise in the incoming web. This dynamism is a major adversity to define and model representative web workload, in fact, this characteristic is not fully represented in the most of the current web workload generators. This work proves that the web user's dynamic behavior is a crucial point that must be addressed in web performance studies in order to accurately estimate system performance indexes. In this paper, we analyze the effect of using a more realistic dynamic workload on the web performance metrics. To this end, we evaluate a typical e-commerce scenario and compare the results obtained using different levels of dynamic workload instead of traditional workloads. Experimental results show that, when a more dynamic and interactive workload is taken into account, performance indexes can widely differ and noticeably affect the stress borderline on the server. For instance, the processor usage can increase 30% due to dynamism, affecting negatively average response time perceived by users, which can also turn in unwanted effects in marketing and fidelity policies. © 2012 Elsevier B.V. All rights reserved.This work has been partially supported by the Spanish Ministry of Science and Innovation under Grant TIN-2009-08201.Peña Ortiz, R.; Gil Salinas, JA.; Sahuquillo Borrás, J.; Pont Sanjuan, A. (2013). Analyzing web server performance under dynamic user workloads. Computer Communications. 36(4):386-395. https://doi.org/10.1016/j.comcom.2012.11.005S38639536

    Composing Identity in Online Instructional Contexts

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    As writing instruction moves from the defined spatial and temporal parameters of the traditional classroom to various degrees of online interaction—from explanatory e-mails to courseware mediated distance education—instructors have had to reconceptualize how they identify themselves to their student audience. While many instructors have tried to translate their face-to-face strategies to the digital medium with disparate degrees of success, others understand the different parameters digital media offer and see new opportunities for literally composing their instructional identity. This contribution will examine the strategies instructors have used to compose their identities with computer-mediated communications and propose suggestions for negotiating this process

    UTJECAJ INFORMATIČKIH MEGATRENDOVA NA GLOBALNE MEGATRENDOVE

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    In this paper, the author analyses the significant influence of IT on global megatrends. Of the five leading global megatrends, two are in the field of ICT, digital media and new technologies. The main reasons for the impact of IT megatrends are twofold: (1) the digital convergence of the media, ICT and telecommunications industries, (2)the exponential increase in information, computing power and internet transfer data. Digital convergence will significantly contribute to changing business models. In an applicative sense, the author considers the concepts of Industry 4.0 - The Fourth Industrial Revolution (4IR), to be the most significant as it marks the paradigmatic change of information, the conceptual and processual transformation of data and services ecosystems in the domains of robotics, the Internet of Things (IoT), Internet of Services, Automated Intelligence, Collaborative Robots (Cobots), Industrial Robots, Augmented Reality, and Virtual Reality. In business and strategic terms, digital media business models will transition, under the influence of digital convergence, to a multi-platform, complementary, interoperable and networked media and ICT ecosystem with a specific focus on the production and distribution of media products, services and applications within the user interface, hypermedia, immersion, mass customization, personalized, augmented and ambient media business space and environment.Autor u ovom radu analizira značajan utjecaj informatičkih na globalne megatrendove. Od pet vodećih globalnih megatrendova, dva se nalaze u području ICT, digitalnih medija i novih tehnologija. Glavni razlozi utjecaja informatičkih megatrendova su dvojaki: (1) Digitalna konvergencija medija, ICT-a i telekomunikacijske industrije, (2) Eksponencijalni porast informacija, kompjutacijske moći i brzine prijenosa podataka. Digitalna konvergencija će značajno doprinijeti promjeni poslovnih modela. U aplikativnom smislu, autor smatra posebno značajnim koncepte Industry 4.0 - The Fourth Industrial Revolution (4IR) koja čini paradigmatsku promjenu informacijske, konceptualne i procesualne transformacije ekosistema podataka i usluga u domenu: robotike, the Internet of Things (IoT), Internet of Services, autonomous vehicles, 3D printing, Smart Cloud, quantum computing, nanotechnology, Big Data (Analytics), cloud computing, edge and fog computing, artificial intelligence, collaborative robots (cobots), industrial robots, augmented reality i virtual reality. U poslovnom i strateškom smislu, poslovni modeli digitalnih medija će se, pod utjecajem digitalne konvergencije, kretati prema multi-platformskom, komplementarnom, interoperabilnom i umreženom medijskom i ICT ekosistemu, sa posebnim fokusom na proizvodnju i distribuciju medijskih proizvoda, usluga i aplikacija u okviru korisničkog interfejsa, hipermedijalnosti, imerzivnosti, masovne kastomizacije/personalizacije, augmentacije i ambijentalizacije medijskog poslovnog prostora i okruženja

    Adaptive and Reactive Rich Internet Applications

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    In this thesis we present the client-side approach of Adaptive and Reactive Rich Internet Applications as the main result of our research into how to bring in time adaptivity to Rich Internet Applications. Our approach leverages previous work on adaptive hypermedia, event processing and other research disciplines. We present a holistic framework covering the design-time as well as the runtime aspects of Adaptive and Reactive Rich Internet Applications focusing especially on the run-time aspects
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